You plan to invest $50,000 in ONE of the following three mutual funds: a) an index fund that passively follows the S&P 500 index, with 0.5% management fee every year; b) an equity fund that actively invests in some famous high-tech firms, with 6% management fee every year; c) a bond fund that invests in a portfolio of bonds issued by central government of different countries, with 2% management fee every year. Which fund do you prefer, and why?